In color toners it is important to have a broad color reproducible region. For this purpose, a linear, low molecular weight-resin having an excellent transparency is mainly used as a resin binder, and the durability thereof, a contradictory property, needs to be improved.
On the other hand, from the viewpoint of the color reproducibility, there have been known a method comprising adding to a toner an additive such as a colorant which has a vivid color and hardly discolors, and a colorless charge control agent, and an ultraviolet absorbent, and a method comprising reacting raw material monomers under a nitrogen atmosphere or under high vacuum in order to improve the color tone of a polyester itself (Japanese Patent Laid-Open No. Hei 8-253562 (U.S. Pat. No. 5,807,654)).
However, the color reproducibility of the color toners is insufficient in both of the above methods. Further improvement in the color reproducibility as well as the durability has been desired.